Reservoir exhaust for core blowing machines



March 20, 1951 R. w. ELLMS 2,545,944

RESERVOIR EXHAUST FOR CORE BLOWING MACHINES Filed June 26, 1948 i 2 Sheets-Sheet 1 JNVENTOR.

ROBERT W. ELI-M BY 06641; 7 J

arroznrzys R. W. ELLMS RESERVOIR EXHAUST FOR CORE BLOWING MACHINES March 20, 1951 Filed June 26, 1948 2 Sheets- Sheet 2 INVENTOR.

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latented Mar. 2 0, 1951 UNITED. STATES PATENT' OFF! CEI arsrnvomrxn i gggg lgconnerowme Robert:W. Ellms,aLakewod, 0hio,=:-assignnr;to The Osborn: Manufacturing :Comnany', Cleveland, ohio -a corporation of Ohio;

Application June 26, 1948;"SerialNo'. 35,413 I This invention relates'as-indicated to.-novel reservoir exhaust means for core blowing ,1mae chines and the like and more particularly to -a device which avoids the disadvantages of prior art arrangements Mold and core blowing machines have longbeen employedby the foundry industry, and oer tain features of their construction have become quitestandardized: Inthose machineswhich are of the semiautomatic type pneumatic mean are quitegenerally employed'to operatethe box clamping means- :andother- -moving parts. Such machines usually. comprise an air chamber, a sand1hopper,:'-and a sand chamber or reservoir laterally moveable into andout of respective sub jacent-engagement therewith; Means are pro vided 'for- :supporting'a core box 'below the sand reservoir when the latter is in blOWingpOSitioh, such means being adapted to be elevated'to bring the top of such core boxinto engagementwiththe lower-end of the reservoir.

In operation, the sand reservoir is filled fromv the sand hopper-and shifted laterally beneath the blow head of: the machine. The core box i then elevatedslightly to tightly'engage the lowerend of the sand'reservoir and high pressure air is ad mittedto the blow head'of-uthemachine to blow. theasand .from the :reservoir into the corebox;

When the blow has-been completed, the :valve' admitting :air'pressure 'to'th'e blow head is closedand an exhaust valve is opened to" relieve the blow head and reservoir ofair pressure prior to such air pressure has been vented through a small exhaust valve in the head of the machine located as far as possible from the'sand reser voir. If this valve is itoo large, the suddenout flow of air creates excessive turbulence and agend deal of sand is'carried along. .Such sand not only causes v'eryrapid wearing of the valve but is also,

discharged intothe room where the machine is located makingfor very unsatisfactory workingconditions By employing a suificiently small vent opening, such turbulence within-the sand reservoir mayibe lessened but the operation of the .machine is slowed in consequence, since the next step inoperation-must await complete vent- 9 Claims; (Cl--22-10.)

ingzof the air pressure. While this may be only amatter of =someseconds,-it is neverthelessrof consequence inthe-caseof a high production ma-i. chineof the type-here in question.

It "is therefore a primar object of my invention to provide *a-reservoir exhaust for core blowing machine which will be very rapid in its action;

Another object of my inventiondsto provide an exhaust which will :not be subject to excessive wear and will require but little maintenance;

Stillanother .objectiiis to "provide such exhaust which-will not discharge sand into-the outer-at e mosphere;

Othenobjects and advantageswill appearas thedescription proceeds.

To 'the accomplishment of the foregoing and related ends, said invention then comprises-the;- features hereinafter fully. described and particularly pointed out in the olaims,-the' following -description and: the annexed drawing setting forthin: detail certain illustrative embodiments of the invention, .thesebeing indicative, however; ofbuta few'of the-various ways in which the principle ofthe invention may be-employed.

In said annexed drawing:

Fig. l is a side elevational view partlyin-oross sectionof a standard well-known type of "a .core blowing machine having the exhaust of my inven' tionincorporated-therein;-

Fig. 2 is a planview' of--my -novel exhaustvalve;

Fig. 3 is a sectionalview taken-alongthe' line 3-3 Orr-Fig. 2;

Fig. '4 is a view taken along the line'--4- -4 on Figr3; and

Fig. 5 is a view taken alongthe line 5 5 on- Fig. 3.

Referring now -more particularly 'to said draw ing, the general construction of the typical core blowing machine illustrated in Fig. 1 will first be. described. Such machine comprisesa 13345616111 1. porting four columns 2 carryingr ,a .sand hopper 3 andia blow head 4 by their upper ends. Blow. head 4 includes an air pressure chamber .-5 andl a blow chamberfi adapted-to-be:-placed intocom-H- munication vorsea-led -,from one another by actuation ofrcliaphragmvalve 1.-

Mounted below blow ,chamberrli-and hopper 3 for lateral. reciprocation into andiout' of respec-- tive subjacent engagement *therewith isa sand;

upon piston H against the force of a coil spring [2.

A table or platen I3 is carried by the upper end of a jackscrew l4 mounted in base I. Such table is adapted to be elevated or lowered through operation of such screw by means of handwheel l5. Adjustably mounted on table l3 are two horizontal clamps l6 and H adapted to be respectively positioned by means of adjusting screws I8 and i9. Clamp H is backed by the piston 20 attached to diaphragm 2|. By admittin air pressure to the left-hand side of such diaphragm as viewed in Fig. 1, clamp I! may be caused to securely hold core box 22 in cooperation with clamp 13. When such air pressure is released, spring 23 will cause clamp I! to move to the left to release such core box. Sand reservoir blow plate 24 is provided with apertures 25 coinciding with similar apertures in the top of the core box whereby sand may be blown from such reservoir into such core box. Screened vents such a 26 will likewise preferably be provided in the core box. to ensure roper compacting of the sand therein. The core box may be either horizontally or vertically split to provide for subsequent removal of the core. Reciprocation of the sand reservoir as above described is controlled by means of the hand operated valve 28 and the treadle operated valve 21 is for controlling the blowing and venting of the reservoir after the blow. It is common practice to provide a circular sand reservoir cover bolted to the side of such reservoir to permit inspection of the interior of the reservoir and manual cleaning thereof should such become necessary. I have provided a novel reservoir exhaust located in the position commonly occupied by such cover plate and in a preferred embodiment comprising a diaphragm valve of large diameter. As shown in Figs. 2-5 inclusive, such valve may comprise a cast iron seat member 29 and a cast iron cover 30 bolted thereto by means of bolts 3|. Valve seat member 29 is secured over annular opening 32 in the side of reservoir 8 by means of studs 33 and nuts 34. Wire mesh screen 35 is clamped between member 29 and the reservoir extending across opening 32 andsealed about its periphery by means of a glue gasket 33. Such screen may, for example, be No. 30 mesh Phosphor bronze, although the exact mesh size preferably employed may vary somewhat depending upon the type of sand bein used in the core blowing operation.

As best shown in Figs. 3 and 4, member 29 is formed on its inner side with a plurality of radially disposed ribs 37 adapted to engage the outer side of wire mesh screen 35. Small protuberances or buttons 38 between such ribs likewise contact-the screen. A large portion of the screen area is therefore available for escape of air therethrough which then passes out through central valve opening 39. Surrounding such central opening 39 is an annular groove 40 connecting with two laterally extending escape passages 4| and 42. A rubber diaphragm 43 is interposed between cover 30 and valve seat member 29 and a connection 44 is provided for the attachment of an air pressure line whereby to operate the valve. A wear-disk or washer 45 is bolted to the center of diaphragm 43 to engage the inside of cover 33 and prevent undue wear of the diaphragm during exhaust.

Referring now more particularly to Figs. 1 and a flexible air line 46 is provided interconnecting asmall aperture 4'! in the blow head and a 4 passage 48 in boss 49 of valve seat member 29. This passage 48 leads into the side of opening 39, thereby providing free escape of air from the upper part of the machine when the valve is open.

The operation and advantages of my new exhaust will now be understood and appreciated. During the blow operation the valv is closed by means of air pressure admitted to cover 30 through opening 44. The pressure on the reservoir side of the diaphragm will be less than on the cover side due to flow of air from the reservoir under the diaphragm out to the exhaust ports. Once the valve is seated, the area of the diaphragm subject to air pressure on the cover side is obviously much greater than area of orifice 39 so the valve remains firmly closed. The moment the blow pressure is shut off and the pressure within cover 30 simultaneously relieved, diaphragm 43 is unseated and the air trapped in the reservoir escapes through screen 35, opening 39 and lateral escape passages 4| and 42. The air escapes very rapidly from the reservoir as a result of the large area of screen 35, but the sand is of course prevented from being carried along thereby. Any sand which accumulates against the screen serves as an additional filter and, since the grains of sands suitable in molding and core blowing operations are always irregular in shape, the body of sand which may accumulate against the screen will be porous in nature. Such sand serves as a desirabl additional filtering medium. If after long use the screen should become clogged, it is a simple matter to change the same. Since the valve assembly is readily removable, no separate clean-out port need be provided. In fact, if desired, the entire valve may be mounted in a hinged door closing such port to facilitate both such cleaning of the reservoir and replacement of the screen. Extended tests, however, have indicated that this will probably not be often necessary. The use of the valve above described permits an extremely rapid drop of pressure within the reservoir from high pressure to low pressure, but I have found that if no additional means is provided there is a disproportionate time lag in the venting of the remaining low pressure air. For this reason I provide the additional vent 41 in the upper part of the machine connecting with passage 48 to the outer side of screen 35. While such vent 41 is too small to provide for sufiiciently rapid escape of high pressure air (a larger opening would cause turbulence and transportation of the sand) nevertheless by providing such direct communication with the exterior atmosphere the escape of the low pressure air remaining within the reservoir, after venting of the high pressure air through screen 35 is obtained. The exact location of opening 41 is not of great consequence as long as it is above the level of the sand remaining in the reservoir and preferably sufficiently thereabove to avoid any likelihood of sand being picked up and transported by the escaping air. Furthermore, since there is no spring or similar means to seatthe diaphragm after the high pressure has been relieved in the reservoir, such diaphragm valve remains open allowing continued escape of the low pressure air.

It will thus be seen that by placing my exhaust directly on the reservoir I have taken advantage of a factor which was previously a definite detriment, namely I obtain a venting of the high pressure air directly from th reservoir and thereby avoid any tendency to lift sand into the head of the machine where its presence ismost objectione haust "operates eiiiciently whether: the sand :level in the reservoir is slightly belowgpartially covers, or completely covers ,the,,scre'en?=35. Thei-term sand as employed herein isofgcourse intended to include other like materials employed in the formation of cores and'moldsiin thefoundry.

The I w'exceedingly .rapid-sidropr of th reservoir pressure permits rapid unclamping and lowering of the core box so that the under surface of the blow plate 24; does not drag across the core box surface when the reservoir is returned to the fill position. This action avoids undue wear and consequential leakage at the joint between blow plate and core box.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims or the equivalent of such be employed.

I therefore particularly point out and distinctly claim as my invention:

1. In a mold and core blowing machine or the like, a sand reservoir having a large opening in the side thereof, blow means above said reservoir operative to blow sand from said reservoir into a core box or the like, filter means adapted to allow passage of air through said opening but adapted to prevent passage of sand therethrough, an air escape passage leading from said opening, and valve means adapted to control fiow of air through said opening operative to place said opening in communication with the outer atmosphere only when a blowing operation is not taking place.

2. In a core blowing machine or the like, a sand reservoir, blow means above said reservoir operative to blow sand from said reservoir into a core box or the like, said reservoir having air exhaust means comprising a large opening in the side thereof positioned to extend at least partially below the level of said sand when said reservoir is filled, filter means disposed across said opening eifective to prevent the escape of sand therethrough, and a valve on said reservoir externally of said opening adapted to control escape of air therethrough, said valve being adapted to close for the duration of the operation of said blow means to prevent passage of air through said opening at such time and to open after completion of the blow to place said opening in communication with the outer atmosphere so that air remaining in said reservoir under pressure may escape.

3. In a mold and core blowing machine, a blow head, a sand reservoir adapted to receive air under pressure from said blow head, two escape passages to relieve air pressure from within said blow head and reservoir, one said passage leading from a large opening in said reservoir provided with sand filter means and the other said passage leading from said blow head and adapted to transmit a much smaller air fiow than said first passage, and valve means controlling escape of air through said passages.

4. In a core blowing machine or the like, a blow head, a sand reservoir, a valve adapted quickly to exhaust high pressure air directly from a side of said reservoir, filter means disposed and ;-;arranged to; prevent :passage :of sand from said-:reservoir through said valve,1:a small air ventiin said 'blowheadspaced-from saidtreservoin and a passageway leading from. said; vent and communicating with the :reservoir- :side 'ofsaid valve between said valve-v and filter means.

5. In a coreblowingmachinaza :blow-head,;a

sand zreservoinua valve mounted on said reservoir adapted to exhaust 'air pressure-:directlyfrom within said reservoir, filter means-disposed and arranged to prevent passage: of sand .from .said reservoir 2 through :said valve, a'smallv air; vent inzrsaid blow head-spaced from". said reservoir, andsaa 'tpassageway leading "from said vent and communicating withuthe reservoirside-of said valve vbetween'isaid valve and filt'ermeans. v

.6.-:Iri;:acore :iblowingj machine or the like, a sand reservoir, a blow head, said reservoir being adapted to be positioned beneath said blow head and having a large opening in the side thereof, a screen disposed across such opening to prevent the passage of sand therethrough, a diaphragm valve exteriorly of said screen operative to place such opening in communication with the outside atmosphere after completion of a blowing operation, a small air vent in said blow head well above the sand level of said reservoir, and a passageway connecting said vent with said valve at a point between said screen and said diaphragm valve.

'7. In a core blowing machine or the like, a sand reservoir, a sand hopper, a blow head, said sand reservoir being alternately reciprocable beneath said sand hopper and blow head and having a large opening in the side thereof, a fine wire mesh screen across such opening, a valve seat member exteriorly of said screen and having a central orifice of less diameter than such opening, projections on said member contacting and supporting said screen, a diaphragm exteriorly of said member operative to seal such orifice in said member, a cover for said diaphragm, means adapted to admit high pressure air to said cover during the core blowing operation to force said diaphragm to seal such orifice, an air exhaust passage in said valve seat member opening toward the inner side of said diaphragm and therefore communicating with such orifice when the latter is not sealed by said diaphragm, a small air vent in said blow head well above the sand level of said reservoir, and a passageway connecting said vent with such central orifice of said valve seat member.

8. In a core blowing machine or the like, a sand reservoir, said reservoir having a large open ing in the side thereof, a screen disposed across said opening to prevent the escape of sand therethrough, a valve seat member exteriorly of said screen and having a central orifice of less diameter than said opening, projections on the inner side of said member contacting and supporting said screen during passage of exhaust air therethrough, an annular groove in the outer side of said member surrounding said central orifice, a-

diaphragm disposed exteriorly of said member operative to seal said orifice, an outer cover for said diaphragm, means adapted to admit high pressure air to said cover during the core blowing operation to force said diaphragm to seal said orifice, and an air exhaust passage leading from said annular groove.

9. In a core blowing machine or the like, a sand reservoir, said reservoir having a large opening in the side thereof, a fine wire mesh screen across said opening adapted to prevent escape of sand therethrough, a valve seat member exteriorly of said screen and opening and having a central orifice of less diameter than said opening, radially disposed ribs on the inner side of said member, buttons on said member between said ribs, said ribs and buttons contacting and supporting said screen during passage of air therethrough, an annular groove in the outer side of said member surrounding such central orifice, a diaphragm disposed exteriorly of said member operative to seal such orifice from said groove, an outer cover for said diaphragm, means adapted to admit high pressure air to said cover during the core blowing operation to force said diaphragm to seal said orifice, and a laterally extending air exhaust passage in said valve seat 15 member leading from said annular groove. ROBERT W. ELLMS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,563,156 Burrnan Nov. 24, 1925 1,594,598 Campbell Aug. 3, 1926" 1,910,417 Zeman May 23, 1933 10 1,919,665 Muller July 25, 1933 FOREIGN PATENTS Number Country Date 227,968 Great Britain Jan. 29, 1925 

